So, if you're come this far, that gets us back to draining the residual energy from our bodies - that's not expelled by movement - into the ground. Let's get back to those upside-down toes. The cones. Our body's own decoupling devices.

We want the shape on the feet to take up as little surface of the ground as possible, and also concentrate on the toes - with the most attention to the big toe. You will often see those experienced in aiki up on their toes and ball of the foot. This creates 7 decoupling cones - one on each toe, and two on the ball - one each near the outside of the ball of the foot.

Irimi - is not a "step." Irimi is a movement - directed by the core. The movement of irimi places major emphasis on the big toe. On the physical level, the big toe is absolutely the business end of irimi - as it decouples the body and drains the energy produced in the body, by the movement of the core, into the ground.

That is where the power of the movement comes from. The power does not result from bringing it up from the ground. There is no power in the ground. The power is created by the continuous flow of positive energy into the body.

Energy that remains in the body when it is not desired, is called "negative energy." Negative energy is great when it runs into the ground. It's not so great when it is in your body. That's having the "sink" back up.

I hope this gives you a better and more accurate understanding of the term "sink."

Hopefully, with these initial notes you understand more about the importance of decoupling. I want to work this into something that's simple with examples that are easy to understand. So, any questions and comments are welcome. Cheers...